The invention relates to a composition comprising solid polymer particles dispersed in a biodissipatable, generally nonaqueous, solvent. The invention further relates to a method of exerting pressure on a selected tissue structure by inserting into tissues adjacent to the selected tissue structure such a composition. More specifically, the invention provides a treatment for those with urinary incontinence and/or vesicoureteral reflux.
surgical implantation of artificial sphincters has often been employed to treat patients suffering from urinary incontinence. The surgical implantation of the artificial sphincter commonly requires hospitalization. In addition, such a procedure is relatively complex and expensive, and will usually require six to eight weeks of recovery time. Moreover, often time, the procedure is unsuccessful or the artificial sphincter malfunctions. As a result, additional surgery is required to adjust, repair or replace the implant.
In the recent past, urinary incontinence may be successfully treated by using nonsurgical means. The most common and widely used method to treat patients with urinary incontinence is periurethral injection of a composition commercially sold as xe2x80x9cPolytefxe2x80x9d. xe2x80x9cPolytefxe2x80x9d is a paste comprising a fifty-fifty (50/50) by weight (corresponding to about 64:36 by volume) mixture of glycerine liquid and Teflon particles. However, after injection, over a period of time the glycerine is readily dissipated into the body and then metabolized or eliminated, leaving only the Teflon particles. This means that only fifty (50) percent of the injected weight remains at the injection site. Consequently the surgeon must inject significantly more volume than he thinks he will need and at times must actually close down the urethra further than is desired. This closure could possibly be complete and thus put the patient into temporary urinary retention. Additionally, the fact that a large portion of the volume disappears makes it difficult for the surgeon to visually gauge how much is an appropriate amount of the Teflon paste to inject. As a result, the surgeon is likely to not inject enough paste volume. The procedure therefore may fail, and a second or even a third procedure to inject additional paste may be required. An additional drawback of the Teflon paste is that the Teflon particle size is sufficiently small so as to allow the particles to migrate to other locations of the body such as the lungs, brain, etc. Teflon particles have been known to induce tissue reaction and form Teflon-induced granulomas in certain individuals. This tissue reaction to Teflon has caused concerns for the patient""s safety.
An alternative to using the Teflon paste is using a collagen suspension. The collagen suspension is injected in the same manner as Teflon paste so as to form a fibrous mass of tissue around the augmentation site. This fibrous mass created by the collagen injection, however, decreases in size and breaks down over time as it is eventually eliminated by the patient""s body. As a result, additional injections are periodically required.
Another alternative which has been investigated but not used other than investigationally is to inject silicone particles dispersed in an aqueous, polyvinylpyrrolidone solution. This combination has the same problem as the Teflon paste in that the polyvinylpyrrolidone solution is readily dissipated away from the area of injection leaving only the volume of silicone particles remaining.
Another material that has been injected is autologous fat. This has had similar problems as the collagen in that the body eventually breaks it down and it disappears.
Devices have been made to attempt to overcome these problems. One device is an inflatable silicone sphere that is passed through a needle and is inflated with saline in the same area that the other materials are injected. There are, however, some problems associated with this device. It is a delicate, mechanical device that is capable of mechanical failure of the valves, shells and structural joints. Another drawback is that the saline filler allows the device to be compliant therefore creating less resistance to the flow of urine. It is also more difficult to place correctly.
Accordingly, it would be desirable to have a composition wherein the mixture is easily administered via injection, generally will not swell or contract to an undesired extent, will be soft enough so as to not cause tissue response/reaction while still being firm enough to provide the required constriction, will not dissipate and will not migrate from the site of injection, thereby enabling the urethra to maintain the initial surgical constriction.
The present invention is directed to overcoming one or more of the problems as set forth above.
One embodiment of the invention is a physiologically acceptable composition comprising a plurality of physiologically acceptable solid polymer particles dispersed in a physiologically acceptable biodissipatable liquid carrier. The solid polymer particles are capable of hydrating, and upon hydration swelling to a predetermined volume. In accordance with a preferred form of this embodiment the liquid carrier is substantially non-aqueous and the solid polymer particles are substantially insoluble in the liquid carrier and in body fluids.
Another embodiment of the invention is a method of exerting pressure on a selected tissue structure by inserting into the tissues adjacent to the tissue structure the above-described physiologically acceptable composition.
Still another embodiment of the invention is a method for increasing urine flow resistance in a patient having urinary incontinence by inserting into the tissues surrounding the patient""s urethra, adjacent to the patient""s urethral sphincter, the above-described physiologically acceptable composition.
Yet another embodiment of the invention is a method for ureteral augmentation in a patient having vesicoureteral reflux by inserting into the tissues adjacent to the patient""s ureteral orifice the above-described physiologically acceptable composition.
Accordingly, the invention provides a nonsurgical, procedure using an easily administered composition for treating patients with urinary incontinence. In addition, the invention obviates the need for re-injections associated with the use of Teflon, collagen, silicone, autologous fat or other similar materials when treating patients with urinary incontinence. By having physiologically acceptable solid polymer particles that will not break down, will not migrate (due to their increased size after swelling) and will not lead to adverse tissue reaction, permanent repair is given to the incontinent patient. Similarly, because of the composition""s properties, it can be used to treat patients suffering from vesicoureteral reflux.